1. Field of the Invention
The present invention relates to a technique of determining information relating to purity of gas contained in a closed space.
2. Description of the Related Art
Conventional methods of measuring information relating to purity of gas in a closed space include the following:
(1) a method of directly measuring the purity of gas such as oxygen (O.sub.2) or the like, which can be easily and directly measured with respect to its concentration by a sensor; and PA1 (2) a method of predicting the purity of gas in a container from the results of measuring the concentration of a specified gas component in gases that leak into a closed space when a large measurement apparatus (for example, a gas flow meter, a mass spectrometer or the like) is required for measuring the concentration of an inert gas such as helium (He) or the like.
However, the conventional methods have the problem that the purity of an inert gas such as helium cannot be easily or precisely measured.